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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
2010-3-23
pubmed:abstractText
The efficacy of a therapeutic IgG molecule may be as dependent on the optimisation of the constant region to suit its intended indication as on the selection of its variable regions. A crucial effector function to be maximised or minimised is antibody-dependent cell-mediated cytotoxicity by natural killer cells. Traditional assays of ADCC activity suffer from considerable inter-donor and intra-donor variability, which makes the measurement of antibody binding to human FcgammaRIIIa, the key receptor for ADCC, an attractive alternative method of assessment. Here, we describe the development of cell lines and assays for this purpose. The transmembrane receptor, FcgammaRIIIa, requires co-expression with signal transducing subunits to prevent its degradation, unlike the homologous receptor FcgammaRIIIb that is expressed as a GPI-anchored molecule. Therefore, to simplify the production of cell lines as reliable assay components, we expressed FcgammaRIIIa as a GPI-anchored molecule. Separate, stable CHO cell lines that express either the 158F or the higher-affinity 158V allotype of FcgammaRIIIa were isolated using fluorescence-activated cell sorting. The identities of the expressed receptors were confirmed using a panel of monoclonal antibodies that distinguish between subclasses and allotypes of FcgammaRIII and the cell lines were shown to have slightly higher levels of receptor than FcgammaRIII-positive peripheral blood mononuclear cells. Because the affinity of FcgammaRIIIa for IgG is intermediate amongst the receptors that bind IgG, we were able to use these cell lines to develop flow cytometric assays to measure the binding of both complexed and monomeric immunoglobulin. Thus, by choosing the appropriate method, weakly- or strongly-binding IgG can be efficiently compared. We have quantified the difference in the binding of wildtype IgG1 and IgG3 molecules to the two functional allotypes of the receptor and report that the FcgammaRIIIa-158V-antibody interaction is 3- to 4-fold stronger that the interaction with FcgammaRIIIa-158F. Overall, these robust assays should be valuable for batch-testing clinical material as well as providing tools for improving the design of therapeutic IgG.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1872-7905
pubmed:author
pubmed:copyrightInfo
2010 Elsevier B.V. All rights reserved.
pubmed:issnType
Electronic
pubmed:day
31
pubmed:volume
354
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
20-33
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed-meshheading:20138184-Amino Acid Sequence, pubmed-meshheading:20138184-Animals, pubmed-meshheading:20138184-Antibodies, Monoclonal, pubmed-meshheading:20138184-Antibody-Dependent Cell Cytotoxicity, pubmed-meshheading:20138184-Base Sequence, pubmed-meshheading:20138184-Biological Assay, pubmed-meshheading:20138184-CHO Cells, pubmed-meshheading:20138184-Cell Separation, pubmed-meshheading:20138184-Cricetinae, pubmed-meshheading:20138184-Cricetulus, pubmed-meshheading:20138184-Flow Cytometry, pubmed-meshheading:20138184-GPI-Linked Proteins, pubmed-meshheading:20138184-Glycosylphosphatidylinositols, pubmed-meshheading:20138184-Humans, pubmed-meshheading:20138184-Immunoglobulin G, pubmed-meshheading:20138184-Leukocytes, Mononuclear, pubmed-meshheading:20138184-Molecular Sequence Data, pubmed-meshheading:20138184-Protein Binding, pubmed-meshheading:20138184-Receptors, IgG, pubmed-meshheading:20138184-Transfection
pubmed:year
2010
pubmed:articleTitle
Expression of human FcgammaRIIIa as a GPI-linked molecule on CHO cells to enable measurement of human IgG binding.
pubmed:affiliation
Division of Immunology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB21QP, UK. kla22@mole.bio.cam.ac.uk
pubmed:publicationType
Journal Article